Now conventional wisdom has been overturned by the results of a study presented at the 2011 Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS).
Pre-run stretching didn't reduce injury rate among amateur runners.
Recent reviews found steroids generally less effective than other therapies.
Acupuncture may ease pain briefly, but we lack evidence to know whether it helps long term healing.
- British study reveals previously unknown reason for “adhesions”, when injured tendons stuck to bone.
This study included 2,729 runners who run 10 or more miles per week. Of these runners, 1,366 were randomly assigned to perform pre-run stretching, and 1,363 were randomized to a no-stretching control group.
Runners in the test group stretched their quadriceps, hamstrings, and gastrocnemius/soleus (back of calf) muscle groups.
The entire routine took 3 to 5 minutes and was performed immediately before running.
The study found that stretching before running neither prevents nor causes injury.
There was no significant difference in injury rates between the runners who stretched and the runners who didn't, for any specific injury location or diagnosis.
Groin pulls, foot-ankle injuries, and knee injuries were the most common kinds reported.
Instead of skipping the pre-run stretch, the results revealed the four top risk factors:
Higher body mass index
The distance run daily … more miles, more risk
History of chronic injury or injury in the past four months
Switching your pre-run routine (i.e., changing from no stretching to stretching, or vice versa)
Runners who typically stretch as part of their pre-run routine and were randomized not to stretch during the study period were far more likely to have an injury.
What about acupuncture?
Two evidence reviews published during the past decade both concluded that acupuncture may provide short term relief for tennis elbow and other tendon injuries.
But there isn't enough good evidence to be able to say whether it can improve long term function.
As a review by the famously rigorous Cochrane Database System concluded, “There is insufficient evidence to either support or refute the use of acupuncture (either needle or laser) in the treatment of lateral elbow pain.” (Green S et al. 2002)
The Cochrane authors went on to detail the evidence:
“This review has demonstrated needle acupuncture to be of short term benefit with respect to pain, but this finding is based on the results of two small trials ... No benefit lasting more than 24 hours following treatment has been demonstrated.” (Green S et al. 2002)
And they made a recommendation that remains unfulfilled: “Further trials utilizing appropriate methodology and adequate sample sizes are needed before firm conclusions can be drawn regarding this treatment modality [acupuncture].” (Green S et al. 2002)
According to British orthopedist Valerie Jones, the author of a more recent review, “The best available evidence is for active exercise approaches, possibly supplemented by manual therapy and taping treatments. There is insufficient evidence to recommend the use of passive modalities such as electrotherapy or acupuncture at present.” (Jones V 2009)
“As a runner myself, I thought stretching before a run would help to prevent injury,” said lead author Daniel Pereles, M.D., an orthopaedic surgeon.
“Although all runners switching routines were more likely to experience an injury than those who did not switch, the group that stopped stretching had more reported injuries, implying that an immediate shift in a regimen may be more important than the regimen itself,” Pereles added (AAOS 2011).
Injured already? Forget about steroids and rest
Once a runner or other aerobic exerciser gets hurt, they naturally want to get back on track as quickly as possible.
And in news related to the stretching study, it appears that neither of the top two recommended therapies – steroid injections and rest – does much to speed recovery.
An evidence review published 17 years ago found not enough evidence to say whether steroid injections help tendon injuries …but noted that they can hinder recovery:
“The decreased tendon strength with intratendinous injections in animal studies suggests that rupture may be a potential complication for several weeks following injection.” (Shrier I et al. 1996)
Now a successor study, published last year by sports medicine experts from Australia's University of Queensland and Griffith University, provides a clearer – albeit not definitive – picture (Coombes BK et al. 2010).
It seems that while steroids can provide short-term pain relief, two other treatments – botulinum toxin and prolotherapy injections – work better in the medium and long term, and sodium hyaluronate injections provided short, medium, and long term relief.
(Hyaluronate is a natural constituent of human connective tissues, used medically for its diverse arthritis-relief and cosmetic skin benefits.)
As the authors put it, “Despite the effectiveness of corticosteroid injections in the short term, non-corticosteroid injections might be of benefit for long-term treatment of lateral epicondylalgia [tennis elbow].” (Coombes BK et al. 2010)
However, as they noted, each patient's individual response to these three standard therapies will vary with his or her physiology, age, and site of injury.
New insights into tendon injury from UK study
In a finding that could lead to new treatments, scientists from the UK discovered how tendons – the fibrous tissue that connects muscle to bone – become damaged through injury or the aging process.
A University of Manchester team, working with colleagues at Glasgow University, have been investigating “adhesions” … the buildup of fibrous tissue on damaged muscle, connective tissues (tendons, ligaments, skin), or internal organs.
The researchers wanted to understand how tendon adhesions form, so they examined the surface of healthy tendons and discovered that they are covered by a thin layer of skin.
Tendons attach our muscles to bone and are essential for movement, and need to glide freely.
When an adhesion forms the tendon can no longer slide over the bone, which causes pain, stiffness and reduced movement.
The UK team discovered that the tendon is actually covered by a thin layer of epithelial cells, which are usually found in skin.
They found that when a tendon's “skin” is damaged, the cells inside the tendon form an unwanted adhesion which begins to stick to nearby tissues.
The authors reported that mice with defective “skin” cells at the surface of their tendons had difficulty walking and spontaneously developed tendon adhesions, even without surgery or injury.
Co-author Dr. Susan Taylor from the University of Manchester made the key point:
“… the discovery of this completely new layer of tendon cells changes the way we are thinking about how tendons are made during embryonic development and maintained in adulthood.”
Their future research aims to find ways of protecting tendons' epithelium coating, with an eye toward preventing and treating adhesions.
[No authors listed] Review: Corticosteroids improve short-term outcomes but worsen longer-term outcomes in some types of tendinopathy. Ann Intern Med. 2011 Feb 15;154(4):JC25.
American Academy of Orthopaedic Surgeons (AAOS). Stretching Before a Run Does Not Prevent Injury. 02/17/2011. Accessed at http://www6.aaos.org/news/pemr/releases/release.cfm?releasenum=974
Coombes BK, Bisset L, Vicenzino B. Efficacy and safety of corticosteroid injections and other injections for management of tendinopathy: a systematic review of randomised controlled trials. Lancet. 2010 Nov 20;376(9754):1751-67. Epub 2010 Oct 21. Review.
Green S, Buchbinder R, Barnsley L, Hall S, White M, Smidt N, Assendelft W. Acupuncture for lateral elbow pain. Cochrane Database Syst Rev. 2002;(1):CD003527. Review.
Jones V. Physiotherapy in the management of tennis elbow: a review. Shoulder & Elbow. Volume 1, Issue 2, pages 108–113, October 2009.
Pereles D, Roth A, Thompson D. The impact of a pre-run stretch on the risk of injury in runners. Podium No: 648; 2011 Annual Meeting Paper Presentations Sports Medicine/Arthroscopy 6: Leg, Ankle, and Arthroscopy. Friday, February 18, 2011. Accessed at http://www3.aaos.org/education/anmeet/anmt2011/podium/podium.cfm?Pevent=648
Shrier I, Matheson GO, Kohl HW 3rd. Achilles tendonitis: are corticosteroid injections useful or harmful? Clin J Sport Med. 1996 Oct;6(4):245-50.
Speed CA. Fortnightly review: Corticosteroid injections in tendon lesions. BMJ. 2001 Aug 18;323(7309):382-6.